Hodgkin's disease is a kind of lymphoma - a cancer of the lymphatic system. The lymphatic system is part of the immune system, which helps the body fight infections and diseases. Lymphatic organs include the spleen, thymus, tonsils, lymph vessels, and lymph nodes. When the cells of the lymphatic system grow uncontrolled, it's called lymphoma. Hodgkin's disease is also called Hodgkin's lymphoma.

Lymph is a fluid that contains white blood cells. Lymph vessels transport it to lymph nodes and other organs of the lymph system. White blood cells are important for fighting infection. When Hodgkin's cancer invades the lymph system, it typically follows the pattern of lymph nodes in the body.